Oxidative stress and anti-oxidative mobilization in burn injury

Relationship of serum paraoxonase enzyme activity and thermal burn injury

OBJECTIVE

This study investigated changes in serum oxidative stress parameters in burn cases compared to healthy controls.

MATERIALS AND METHODS

This study was performed in 41 burn patients with mild to severe thermal burn injuries and 38 healthy volunteers. The burn cases were selected from patients who were hospitalized in the burn unit for the treatment of second- and third-degree burns. Malondialdehyde (MDA) levels and PON-1 paraoxonase and arylesterase activities were measured in patient serum samples.

RESULTS

PON-1 paraoxonase activity and MDA levels in patients with major thermal burn injury were significantly higher than healthy controls, but PON-1 arylesterase activities were lower. A significant negative correlation was observed between the burn percentage of the total body surface area and the PON-1 arylesterase activities in patients.

CONCLUSION

Human thermal burn injury was associated with an increase in MDA production and a decrease in PON-1 arylesterase activity, which was proportional to the percentage of total burned surface area.

Topical N-acetylcysteine improves wound healing comparable to dexpanthenol: an experimental study

In this study, we aimed to compare the effects of dexpanthenol and N-acetylcysteine on wound healing. The wound healing process is a multifaceted sequence of activities associated with tissue restoration process. A number of investigations and clinical studies have been performed to determine new approaches for the improvement of wound healing. A total of 30 rats were divided into 3 equal groups. A linear 2-cm incision was made in the rats' skin. No treatment was administered in the first (control) group. Dexpanthenol cream was administered to the rats in the second group and 3% N-acetylcysteine cream was administered to the rats in the third group. The wound areas of all of the rats were measured on certain days. On the 21st day, all wounds were excised and histologically evaluated. The epithelialization and granulation rates between the groups were revealed to be similar in microscopic evaluations. Although the fibrosis was remarkable in the control group as compared with the other groups, it was similar in N-acetylcysteine and dexpanthenol groups. Angiogenesis rate was remarkable in the N-acetylcysteine group compared with the others. In multiple-comparison analysis, Dexpanthenol and N-acetylcysteine groups had similar results in terms of wound healing rates (P < 0.05), which were both higher than in the control group (P > 0.05). The efficacy of N-acetylcysteine in wound healing is comparable to dexpanthenol, and both substances can be used to improve wound healing.

Spontaneous neutrophil migration patterns during sepsis after major burns

Finely tuned to respond quickly to infections, neutrophils have amazing abilities to migrate fast and efficiently towards sites of infection and inflammation. Although neutrophils ability to migrate is perturbed in patients after major burns, no correlations have yet been demonstrated between altered migration and higher rate of infections and sepsis in these patients when compared to healthy individuals. To probe if such correlations exist, we designed microfluidic devices to quantify the neutrophil migration phenotype with high precision. Inside these devices, moving neutrophils are confined in channels smaller than the neutrophils and forced to make directional decisions at bifurcations and around posts. We employed these devices to quantify neutrophil migration across 18 independent parameters in 74 blood samples from 13 patients with major burns and 3 healthy subjects. Blinded, retrospective analysis of clinical data and neutrophil migration parameters revealed that neutrophils isolated from blood samples collected during sepsis migrate spontaneously inside the microfluidic channels. The spontaneous neutrophil migration is a unique phenotype, typical for patients with major burns during sepsis and often observed one or two days before the diagnosis of sepsis is confirmed. The spontaneous neutrophil migration phenotype is rare in patients with major burns in the absence of sepsis, and is not encountered in healthy individuals. Our findings warrant further studies of neutrophils and their utility for early diagnosing and monitoring sepsis in patients after major burns.

The characteristics and correlation between the ischemia-reperfusion and changes of redox status in the early stage of severe burns

OBJECTIVE

Both the ischemia-reperfusion injury and the abnormal changes of redox status are the important pathologic changes in the burn shock stage for severe burns. The study of clinical dynamic, quantitative relevance about them was performed.

METHODS

In this study, blood redox potential (ORP) values (ΔORP value was adopted, as the quantitative index to reflect the overall redox status), plasma uric acid levels (important antioxidant, as antioxidant index), and the burn shock state-related indicators (lactic acid and hematocrit) of 48 burn patients were dynamically, quantitatively monitored during the early stage after injury.

RESULTS

The results revealed that the duration of abnormal fluctuation of redox status in the early stage of severe burns was longer than that of the traditional clinical shock stage (2-3 days). The changes of overreduction soon after injury were closely related to the hypovolemia-related hypoxia, and the following overoxidation status was consistent with the pathophysiological changes related to the reperfusion, and the degrees of variation were closely related to the severity of burn injury and prognosis. Moreover, early surgery (3 days after injury) had no significant influence on the changing trend of abnormal redox status in the early stage of severe burns.

CONCLUSION

The ischemia-reperfusion injury caused by burn shock appears the main factor contributing to the abnormal biphasic changes of redox status in the early stage of severe burns. Our findings provide useful information for the redox regulation treatment for burn shock.

Micronutrients after burn injury: a review

Supplementation of micronutrients after burn injury is common practice in order to fight oxidative stress, support the immune system, and optimize wound healing. Assessing micronutrient status after burn injury is difficult because of hemodilution in the resuscitation phase, redistribution of nutrients from the serum to other organs, and decreases in carrier proteins such as albumin. Although there are many preclinical data, there are limited studies in burn patients. Promising research is being conducted on combinations of micronutrients, especially via the intravenous route.

Biphasic changes (overreduction and overoxidation) of plasma redox status and clinical implications in early stage of severe burns

PURPOSE

Although the changes of redox status in the early stage of severe burns are considered to be associated with the disease progression, whereas antioxidant therapy cannot improve the prognosis, the characteristics and mechanisms of dynamic change of redox status related with the disease progression deserve further study.

METHODS

Blood redox potential (ORP) values (ΔORP value was adopted), plasma uric acid (UA) levels, and the inflammation-related indicators of 67 burn patients were dynamically monitored in the early stage.

RESULTS

Compared with healthy persons, the results revealed the biphasic changes of redox status in the early stage after burns, and both of them were closely related to the prognosis of severe burns. Overreduction status and overoxidation status were related to the dynamic changes of plasma UA level and the inflammation-related indicators of severe burns. In addition, the change of ΔORP value was found to associate with the traditional prognostic markers.

CONCLUSIONS

This study firstly revealed the excessive, biphasic changes of redox status and clinical implications in the early stage of severe burns, providing a new viewpoint for early pathological changes of severe burns and will be helpful for corresponding early treatment. ΔORP value also appears to be a potential early prognostic marker.

Expression of DNA repair genes in burned skin exposed to low-level red laser

Although red laser lights lie in the region of non-ionizing radiations in the electromagnetic spectrum, there are doubts whether absorption of these radiations causes lesions in the DNA molecule. Our aim was to investigate the expression of the genes involved with base excision and nucleotide excision repair pathways in skin tissue submitted to burn injury and exposed to low-level red laser. Wistar rats were divided as follows: control group-rats burned and not irradiated, laser group-rats burned and irradiated 1 day after injury for five consecutive days, and later laser group-rats injured and treated 4 days after injury for five consecutive days. Irradiation was performed according to a clinical protocol (20 J/cm(2), 100 mW, continuous wave emission mode). The animals were sacrificed on day 10, and scarred tissue samples were withdrawn for total RNA extraction, complementary DNA (cDNA) synthesis, and evaluation of gene expression by quantitative polymerase chain reaction. Low-level red laser exposure (1) reduces the expression of APE1 messenger (mRNA), (2) increases the expression of OGG1 mRNA, (3) reduces the expression of XPC mRNA, and (4) increases the expression of XPA mRNA both in laser and later laser groups. Red laser exposure at therapeutic fluences alters the expression of genes related to base excision and nucleotide excision pathways of DNA repair during wound healing of burned skin.

Topical N-acetylcysteine accelerates wound healing in vitro and in vivo via the PKC/Stat3 pathway

N-Acetylcysteine (Nac) is an antioxidant administered in both oral and injectable forms. In this study, we used Nac topically to treat burn wounds in vitro and in vivo to investigate mechanisms of action. In vitro, we monitored glutathione levels, cell proliferation, migration, scratch-wound healing activities and the epithelialization-related proteins, matrixmetalloproteinase-1 (MMP-1) and proteins involved in regulating the expression of MMP-1 in CCD-966SK cells treated with Nac. Various Nac concentrations (0.1, 0.5, and 1.0 mM) increased glutathione levels, cell viability, scratch-wound healing activities and migration abilities of CCD-966SK cells in a dose-dependent manner. The MMP-1 expression of CCD-966SK cells treated with 1.0 mM Nac for 24 h was significantly increased. Levels of phosphatidylinositol 3-kinase (PI3K), protein kinase C (PKC), janus kinase 1 (Jak1), signal transducer and activator of transcription 3 (Stat3), c-Fos and Jun, but not extracellular signal-regulated protein kinases 1 and 2 (Erk1/2), were also significantly increased in a dose-dependent manner compared to the controls. In addition, Nac induced collagenous expression of MMP-1 via the PKC/Stat3 signaling pathway. In vivo, a burn wound healing rat model was applied to assess the stimulation activity and histopathological effects of Nac, with 3.0% Nac-treated wounds being found to show better characteristics on re-epithelialization. Our results demonstrated that Nac can potentially promote wound healing activity, and may be a promising drug to accelerate burn wound healing.

Melatonin protection against burn-induced liver injury. A review

Severe thermal injury may be complicated by dysfunction of organs distant from the original burn wound, including the liver, and represents a serious clinical problem. Although pathophysiology of burn-induced liver injury remains unclear, increasing evidence implicate activation of inflammatory response, oxidative stress, endothelial dysfunction and microcirculatory disorders as the main mechanisms of hepatic injury. Several studies suggest melatonin as a multifunctional indolamine that counteracts some of the pathophysiologic steps and displays significant beneficial effects against burn-induced cellular injury. This review summarizes the role of melatonin in restricting the burn-induced hepatic injury and focuses on its effects on oxidative stress, inflammatory response, endothelial dysfunction and microcirculatory disorders as well as on signaling pathways such as regulation of nuclear erythroid 2-related factor 2 (Nrf2) and nuclear factor-kappaB (NF-kB). Further studies are necessary to elucidate the modulating effect of melatonin on the transcription factor responsible for the regulation of the pro-inflammatory and antioxidant genes involved in burn injuries.

Antiinflammatory effects of Viola tricolor gel in a model of sunburn in rats and the gel stability study

ETHNOPHARMACOLOGICAL RELEVANCE

Viola tricolor, popularly known as heartsease has been empirically used in several skin disorders, including burns.

AIM OF THE STUDY

The objective of this study was investigate the antinociceptive and antiinflammatory effect of a gel containing extract of Viola tricolor flowers on thermal burn induced by UVB irradiation and to perform gel stability study.

METHODS

The antinociceptive and antiinflammatory effect were evaluated by static and dynamic mechanical allodynia model, paw edema, and neutrophilic cell infiltration. Metabolites compounds were quantified by HPLC. The gel stability study was performed analyzing organoleptical aspects, besides pH, viscosity, and quantification of rutin by HPLC.

RESULTS

In the results were evidenced changes in threshold in statical and dynamic mechanical allodynia (I(max)=100 ± 10% and 49 ± 10%, respectively), paw edema (I(max)=61 ± 6%), and myeloperoxidase activity (I(max)=89 ± 5%). Such effects may be attributed, in part, to rutin, salicylic and chlorogenic acids, and others compounds found in this species. No important changes were detected in the stability study, in all aspects analyzed in temperature below 25 °C.

CONCLUSION

These findings suggest that Viola tricolor gel has an antinociceptive and antiinflammatory effect in the ultraviolet-B-induced burn, since maintain the temperature below 25 °C.

Indocyanine green dye angiography accurately predicts survival in the zone of ischemia in a burn comb model

INTRODUCTION

Surgical evaluation of burn depth is performed via clinical observation, with only moderate reliability. While perfusion analysis has been proposed to enhance accuracy, no perfusion study has attempted to predict burn extension into the area of ischemia surrounding the original insult. We examined whether laser Doppler imaging (LDI) and indocyanine green (ICG) angiography predicted survival in the zone of ischemia in a porcine hot comb burn model.

METHODOLOGY

Six full-thickness wounds were created on 5 female Yorkshire swine using a validated porcine hot comb burn model. 4 full-thickness burns were created separated by 3 unburned interspaces that represent the zone of ischemia. The interspaces between each comb burn were monitored using LDI and ICG Angiography at 1, 4, 24, and 48 h after burn. Interspace survival was assessed via gross observation and blinded histological readings 7 days after injury.

RESULTS

ICG Angiographic assessments of burn perfusion were significantly different in viable vs. non-viable interspace perfusion at 1 h, 4 h, and 48 h. Temporal plotting of a trend-line derived from quantitative perfusion measurements rendered two distinct graphs, allowing for the derivation of a predictive algorithm to separate viable and non-viable interspaces. LDI revealed no such prognostic trend.

CONCLUSION

Results from a validated porcine burn comb model suggest that ICG angiography has significant potential in the prediction of burn progression early after burn. However, the full potential of this technology cannot be determined until completion of clinical trials.

Effect of acute thermal injury in status of serum vitamins, inflammatory markers, and oxidative stress markers: preliminary data

The objective of this study was to evaluate the vitamin status, inflammatory markers, and oxidative stress markers in adult patients up to 3 days after thermal injury. This prospective study was conducted with 11 patients 24 to 72 hours after thermal injury (Burn Group), total surface area ranging from 10 to 41%, 34.3 ± 9.3 years, 82% of males, body mass index of 22.3 ± 2.9 kg/m(2). We included 11 healthy adults (Control Group), 36.5 ± 7.6 years, 73% of males, and body mass index of 23.8 ± 2.5 kg/m(2). Laboratory data were measured (plasma total protein, albumin, transferrin, lymphocyte counts, zinc, and iron), as well as serum vitamins (folic acid, vitamin B12, and vitamins A, C, and E), inflammatory stress markers (C-reactive protein, ferritin, and acid α1-glycoprotein) and oxidative stress markers such as glutathione peroxidase (GPx) and thiobarbituric acid reactive substances. The inflammatory stress was characterized by lower levels of total protein (median difference 1.2 g/dL, 95% CI: 0.4-2.1) and albumin (median difference 0.9 g/dL, 95% CI: 0.5-1.5), and higher levels of C-reactive protein (median difference -8.12 mg/dL, 95% CI: -11.62 to 4.61) and α-1 glycoprotein acid (median difference -28.56 mg/dL, 95% CI: -51.57 to -5.07) in burn patients. Decreased serum levels of vitamin A (median difference 1.10 μmol/L, 95% confidence interval [CI]: 0.42-1.66) and vitamin C (median difference 0.82 mg/dL, 95% CI: 0.50-1.04) were also detected. There was no statistical evidence of difference in the serum levels of glutathione peroxidase and thiobarbituric acid reactive substances between burn patients and controls, respectively. Even though there is an inflammatory stress, the obtained data showed that oxidative stress markers are normal 24 to 72 hours after burn injury. The decrease in negative acute phase protein may account for the diminished serum levels of vitamin A, which seems to be related to inflammatory stress. The marked decrease in the serum levels of vitamin C can be justified by augmented cutaneous loss and consumption in the regeneration of vitamin E.

Effect of 200 mEq/L Na+ hypertonic saline resuscitation on systemic inflammatory response and oxidative stress in severely burned rats

BACKGROUND

Excessive release of inflammatory mediators and oxidative stress play important roles in the increased vascular permeability and systemic edema during the early stage of severe burn. This study investigates the effect of 200 mEq/L Na(+) hypertonic saline (HS) on systemic inflammatory response and oxidative stress in severely burned rats.

MATERIALS AND METHODS

Sprague-Dawley rats were divided into three groups: sham group, burn plus lactated Ringer's group, and burn plus HS group. Lung edema was assessed in terms of wet-weight-to-dry-weight ratio. Tumor necrosis factor α and interleukin 6 concentrations in serum were examined by enzyme-linked immunosorbent assay. Peripheral blood mononuclear cells were isolated and the expression of p38 mitogen-activated protein kinase was determined by Western blot analysis. The lung and intestinal concentrations of malondialdehyde, an indicator of oxidative stress, were also measured.

RESULTS

Resuscitation with 200 mEq/L Na(+) HS significantly decreased the lung wet-weight-to-dry-weight ratio and abolished hyponatremia induced by burn injury. HS treatment also prevented the increases of myeloperoxidase activity and malondialdehyde content in the lung and intestine of severely burned rats. However, there were no significant differences, either in serum tumor necrosis factor α and interleukin 6 concentrations or with respect to the p38 mitogen-activated protein kinase expression in peripheral blood mononuclear cells, between the burn plus lactated Ringer's group and burn plus HS group (P > 0.05).

CONCLUSIONS

Initial resuscitation with 200 mEq/L Na(+) HS after severe burn injury decreases pulmonary edema, prevents hyponatremia, and attenuates oxidative stress, but is not capable of inhibiting the systemic inflammatory response.

The reliability of clinical dynamic monitoring of redox status using a new redox potential (ORP) determination method

PURPOSE

Quantitative monitoring of the redox status is the foundation for redox-related treatment. The purpose of this study was to evaluate the reliability of a new depolarization curve method for plasma redox potential (ORP) monitoring.

METHODS

Using the new method, we performed redox determinations for the first time under different sample-handling conditions, including redox titration experiments using KMnO4 and vitamin C and dynamic redox monitoring in burn patients. The relative ORP value (ΔORP) method (improved traditional method) was used as the reference.

RESULTS

The new method's better reliability, electrochemical specificity and practicability, and known group validity, which are closely associated with the redox-related pathological processes of severe burns, were confirmed. Furthermore, bidirectional change in the redox status in severe burn patients was also observed for the first time.

CONCLUSIONS

This simple, stable new method could be a better practical tool for making the dynamic monitoring of the redox status feasible and for providing useful quantitative information for the judgment of redox-related pathological process, thus improving corresponding individualized treatments that rely on quantitative adjustments to the redox status.

Glycolipid biosurfactants, mannosylerythritol lipids, show antioxidant and protective effects against H(2)O(2)-induced oxidative stress in cultured human skin fibroblasts

Mannosylerythritol lipids (MELs) are biosurfactants known for their versatile interfacial and biochemical properties. To broaden their application in cosmetics, we investigated the antioxidant properties of different MEL derivatives (MEL-A, -B, and -C) by using a 1,1-diphenyl-2-picryl hydrazine (DPPH) free-radical- and superoxide anion-scavenging assay. All MEL derivatives tested showed antioxidant activity in vitro, but at lower levels than those of arbutin. Of the MELs, MEL-C, which is produced from soybean oil by Pseudozyma hubeiensis, showed the highest rates of DPPH radical scavenging (50.3% at 10 mg/mL) and superoxide anion scavenging (>50% at 1 mg/mL). The antioxidant property of MEL-C was further examined using cultured human skin fibroblasts (NB1RGB cells) under H(2)O(2) induced oxidative stress. Surprisingly, MEL-C had a higher protective activity against oxidative stress than arbutin did: 10 µg/mL of MEL-C and arbutin had protective activities of 30.3% and 13%, respectively. Expression of an oxidative stress marker, cyclooxygenase-2, in these cells was repressed by treatment with MEL-C as well as by arbutin. MEL-C was thus confirmed to have antioxidant and protective effects in cells, and we suggest that MELs have potential as anti-aging skin care ingredients.

Antinociceptive and anti-inflammatory effects of Aloe saponaria Haw on thermal injury in rats

ETHNOPHARMACOLOGICAL RELEVANCE

In Brazil, the plant Aloe saponaria Haw, popularly known as "babosa pintadinha", has been empirically used for its potential effect on thermal injury. Because there are no scientific data confirming its popular use, the aim of the present study was to investigate the effects of Aloe saponaria on nociceptive and inflammatory parameters in a rat model of thermal injury.

MATERIALS AND METHODS

Adult male Wistar rats were subjected to a thermal injury or sham procedure (immersion in water at 70 or 37°C, respectively, for 5 or 8s). Burned animals were topically treated with vehicle (base cream), sulfadiazine 1% (positive control) or Aloe saponaria cream (0.3%-30%) once a day for 2 or 6 days. Each day, 30min before the treatment, we measured nociceptive (static and dynamic mechanical allodynia, thermal allodynia and spontaneous pain) and inflammatory (paw edema) parameters. Moreover, enzymatic indicators of leukocyte infiltration into burned tissue were also determined 2 or 6 days after the thermal injury.

RESULTS

The thermal injury (fist and second-degree) procedure, but not the sham procedure, induced nociception and inflammation from 1 to 6 days after the injury. The topical treatment with Aloe saponaria cream (10%) reduced nociceptive behaviors from day 1 to 6 (peak at day 2), edema at days 5 and 6 (peak at day 6) and myeloperoxidase, N-acetyl-glucosaminidase and eosinoperoxidase activities at day 6. The antinociceptive and anti-inflammatory effects of Aloe saponaria were obtained with doses of 3%-30%, with maximal inhibition obtained with a dose of 10% (reductions of 39±9%, 41±9%, 31±7%, 83±7% and 23±2% for static and dynamic mechanical allodynia, thermal allodynia, spontaneous pain and paw edema, respectively).

CONCLUSION

Our results demonstrate that topically applied Aloe saponaria presented antinociceptive and anti-inflammatory effects in rats subjected to a thermal injury, which supports its traditional use for burn injuries.

Severe burn injury, burn shock, and smoke inhalation injury in small animals. Part 1: burn classification and pathophysiology

OBJECTIVE

To review the literature related to severe burn injury (SBI), burn shock, and smoke inhalation injury in domestic animals. Current animal- and human-based research and literature were evaluated to provide an overview of thermal burn classification and the pathophysiology of burn shock and smoke inhalation injury.

ETIOLOGY

Severe burn injury, burn shock, and smoke inhalation injury may be encountered as a result of thermal injury, radiation injury, chemical injury, or electrical injury.

DIAGNOSIS

Burns can be subdivided based on the amount of total body surface area (TBSA) involved and the depth of the burn. Local burn injuries involve <20% of the TBSA whereas SBI involves >20-30% of the TBSA. The modern burn classification system classifies burns by increasing depth: superficial, superficial partial-thickness, deep partial-thickness, and full-thickness.

SUMMARY

Local burn injury rarely leads to systemic illness whereas SBI leads to significant metabolic derangements that require immediate and intensive management. SBI results in a unique derangement of cardiovascular dysfunction known as "burn shock." The physiologic changes that occur with SBI can be divided into 2 distinct phases; the resuscitation phase and the hyperdynamic hypermetabolic phase. The resuscitation phase occurs immediately following SBI and lasts for approximately 24-72 hours. This period of hemodynamic instability is characterized by the release of inflammatory mediators, increased vascular permeability, reduced cardiac output, and edema formation. The hyperdynamic hypermetabolic phase begins approximately 3-5 days after injury. This phase is characterized by hyperdynamic circulation and an increased metabolic rate that can persist up to 24 months post burn injury in people.

Severe burn injury, burn shock, and smoke inhalation injury in small animals. Part 2: diagnosis, therapy, complications, and prognosis

OBJECTIVE

To review the evaluation and treatment of patients suffering from severe burn injury (SBI), burn shock, and smoke inhalation injury. Potential complications and prognosis associated with SBI are also discussed.

DIAGNOSIS

Diagnosis of burn injury and burn shock is based on patient history and clinical presentation. Superficial burn wounds may not be readily apparent for the first 48 h whereas more severe wounds will be evident at presentation. Patients are diagnosed with local or SBI by estimating total body surface area involved using the 'Rule of Nines' or the Lund-Browder chart adapted from the human literature.

THERAPY

Patients suffering from SBI require immediate and aggressive fluid therapy. Burn wounds require prompt cooling to prevent progressive tissue damage. Due to significant pain associated with burn wounds and therapeutic procedures, multimodal analgesia is recommended. Daily wound management including hydrotherapy, topical medications, and early wound excision and grafting is necessary with SBI.

COMPLICATIONS

There are numerous complications associated with SBI. The most common complications include infections, hypothermia, intra-abdominal hypertension, and abdominal compartment syndrome.

PROGNOSIS

The prognosis of SBI in domestic animals is unknown. Based on information derived from human literature, patients with SBI and concomitant smoke inhalation likely have a worse prognosis than those with SBI or smoke inhalation alone.

Brown adipose tissue and its modulation by a mitochondria-targeted peptide in rat burn injury-induced hypermetabolism

Hypermetabolism is a prominent feature of burn injury, and altered mitochondria function is presumed to contribute to this state. Recently, brown adipose tissue (BAT) was found to be present not only in rodents but also in humans, and its activity is associated with resting metabolic rate. In this report, we elucidate the relationship between burn injury-induced hypermetabolism and BAT activity and the possible role of the mitochondria-targeted peptide SS31 in attenuating burn injury-induced hypermetabolism by using a rat burn injury model. We demonstrate that burn injury induces morphological changes in interscapular BAT (iBAT). Burn injury was associated with iBAT activation, and this effect was positively correlated with increased energy expenditure. BAT activation was associated with augmentation of mitochondria biogenesis, and UCP1 expression in the isolated iBAT mitochondria. In addition, the mitochondria-targeted peptide SS31 attenuated burn injury-induced hypermetabolism, which was accompanied by suppression of UCP1 expression in isolated mitochondria. Our results suggest that BAT plays an important role in burn injury-induced hypermetabolism through its morphological changes and expression of UCP1.

The prevalence of human endogenous retroviruses in the plasma of major burn patients

BACKGROUND

Approximately 8% of the human genome is composed of retroviral sequences, which are known as human endogenous retroviruses (HERVs) and, have been implicated in both health status and disease. Recently, indirect evidence for a possible role of retroviral elements in the systemic response to stress signals has been provided by several studies. In the present study, we sought to evaluate the relationship between HERVs and major burn in humans.

METHOD

We investigated the prevalence of HERV families by reverse transcriptase PCR (RT-PCR) in cell-free plasma samples from patients with burns and from normal individuals.

RESULTS

Different prevalences of HERV families were observed in the plasma samples from the burn patient group and normal group. Compared with the prevalences of HERV-W and HERV-K in the normal group, in the burn patient group, the prevalence of HERV-W was significantly lower (P<0.001), but the prevalence of HERV-K was higher (P=0.059).

CONCLUSIONS

Our study of the prevalences of HERVs revealed that the activation of certain HERV families may be influenced not only by burns but also by the initial treatments that were used to address these injuries.

Sustained oxidative stress causes late acute renal failure via duplex regulation on p38 MAPK and Akt phosphorylation in severely burned rats

BACKGROUND

Clinical evidence indicates that late acute renal failure (ARF) predicts high mortality in severely burned patients but the pathophysiology of late ARF remains undefined. This study was designed to test the hypothesis that sustained reactive oxygen species (ROS) induced late ARF in a severely burned rat model and to investigate the signaling mechanisms involved.

MATERIALS AND METHODS

Rats were exposed to 100°C bath for 15 s to induce severe burn injury (40% of total body surface area). Renal function, ROS generation, tubular necrosis and apoptosis, and phosphorylation of MAPK and Akt were measured during 72 hours after burn.

RESULTS

Renal function as assessed by serum creatinine and blood urea nitrogen deteriorated significantly at 3 h after burn, alleviated at 6 h but worsened at 48 h and 72 h, indicating a late ARF was induced. Apoptotic cells and cleavage caspase-3 in the kidney went up slowly and turned into significant at 48 h and 72 h. Tubular cell ROS production shot up at 6 h and continuously rose during the 72-h experiment. Scavenging ROS with tempol markedly attenuated tubular apoptosis and renal dysfunction at 72 h after burn. Interestingly, renal p38 MAPK phosphorylation elevated in a time dependent manner whereas Akt phosphorylation increased during the first 24 h but decreased at 48 h after burn. The p38 MAPK specific inhibitor SB203580 alleviated whereas Akt inhibitor exacerbated burn-induced tubular apoptosis and renal dysfunction. Furthermore, tempol treatment exerted a duplex regulation through inhibiting p38 MAPK phosphorylation but further increasing Akt phosphorylation at 72 h postburn.

CONCLUSIONS

These results demonstrate that sustained renal ROS overproduction induces continuous tubular cell apoptosis and thus a late ARF at 72 h after burn in severely burned rats, which may result from ROS-mediated activation of p38 MAPK but a late inhibition of Akt phosphorylation.

Moderate systemic hypothermia decreases burn depth progression

BACKGROUND

Therapeutic hypothermia has been proposed to be beneficial in an array of human pathologies including cardiac arrest, stroke, traumatic brain and spinal cord injury, and hemorrhagic shock. Burn depth progression is multifactorial but inflammation plays a large role. Because hypothermia is known to reduce inflammation, we hypothesized that moderate hypothermia will decrease burn depth progression.

METHODS

We used a second-degree 15% total body surface area thermal injury model in rats. Burn depth was assessed by histology of biopsy sections. Moderate hypothermia in the range of 31-33°C was applied for 4h immediately after burn and in a delayed fashion, starting 2h after burn. In order to gain insight into the beneficial effects of hypothermia, we analyzed global gene expression in the burned skin.

RESULTS

Immediate hypothermia decreased burn depth progression at 6h post injury, and this protective effect was sustained for at least 24h. Burn depth was 18% lower in rats subjected to immediate hypothermia compared to control rats at both 6 and 24h post injury. Rats in the delayed hypothermia group did not show any significant decrease in burn depth at 6h, but had 23% lower burn depth than controls at 24h. Increased expression of several skin-protective genes such as CCL4, CCL6 and CXCL13 and decreased expression of tissue remodeling genes such as matrix metalloprotease-9 were discovered in the skin biopsy samples of rats subjected to immediate hypothermia.

CONCLUSIONS

Systemic hypothermia decreases burn depth progression in a rodent model and up-regulation of skin-protective genes and down-regulation of detrimental tissue remodeling genes by hypothermia may contribute to its beneficial effects.

Resolvin D2 prevents secondary thrombosis and necrosis in a mouse burn wound model

Deep partial thickness burns are subject to delayed necrosis of initially viable tissues surrounding the primary zone of thermally induced coagulation, which results in an expansion of the burn wound, both in area and depth, within 48 hours postburn. Neutrophil sequestration and activation leading to microvascular damage is thought to mediate this secondary tissue damage. Resolvins, a class of endogenous mediators derived from omega-3 polyunsaturated fatty acids, have been shown to regulate the resolution of inflammation. We hypothesized that exogenous resolvins could mitigate the deleterious impact of the inflammatory response in burn wounds. Using two different mouse burn injury models involving significant partial thickness injuries, we found that a systemically administered single dose of resolvin D2 (RvD2) as low as 25 pg/g bw given within an interval of up to 4 hours postburn effectively prevented thrombosis of the deep dermal vascular network and subsequent dermal necrosis. By preserving the microvascular network, RvD2 enhanced neutrophil access to the dermis, but prevented neutrophil-mediated damage through other anti-inflammatory actions, including inhibition of tumor necrosis factor-α, interleukin-1β, and neutrophil platelet-endothelial cell adhesion molecule-1. In a clinical context, RvD2 may be therapeutically useful by reducing the need for surgical debridement and the area requiring skin grafting.

An effective antioxidant drug on prevention of the necrosis of zone of stasis: N-acetylcysteine

The zone of stasis, the encircling area of the zone of coagulation, is a critical area which determines the depth and width of the necrosis in burns. Many agents were proposed to salvage the zone of stasis. Due to the known preventive and therapeutic effects of N-acetylcysteine on hepatotoxicity, nephrotoxicity, pulmonary injury, and multiple organ failure in humans, the effect of N-acetylcysteine on saving the zone of stasis was investigated in this experimental study. The effects of N-acetylcysteine administration via oral or intraperitoneal route was compared in a rat comb-burn model. The extent of burn wounds was evaluated by photography and planimetry in the groups. Additionally, skin samples were obtained to analyze malondialdehyde levels to see the antioxidant effect of N-acetylcysteine. In control group (no treatment), the burn areas went to near total necrosis. In intraperitoneal and oral treatment groups, skin survival occurred in the interspace area of the comb. There was no difference between the groups in terms of MDA concentrations. In conclusion, this study showed us the possible saving effect of N-acetylcysteine on the zone of stasis. N-acetylcysteine may be used in the cases of severe burns, not only for its effects on wound healing but also the systemic effects of the drug.

Madecassoside, a triterpenoid saponin isolated from Centella asiatica herbs, protects endothelial cells against oxidative stress

This study aimed to investigate the effect of madecassoside against oxidative stress-induced injury of endothelial cells. Hydrogen peroxide (H(2)O(2), 500 µmol/L) was employed as an inducer of oxidative stress in human umbilical vein endothelial cells (HUVECs). Cell apoptosis was detected by Hoechst 33258 staining and flow cytometry. Caspase-3 activity and mitochondria membrane potential were further examined. As a result, madecassoside (10, 30, 100 µmol/L) could reverse morphological changes, elevate cell viability, increase glutathione levels, and decrease lactate dehydrogenase and malondialdehyde levels caused by H(2)O(2) in a concentration-dependent manner. It attenuated apoptosis, preventing the activation of caspase-3 and the loss of mitochondria membrane potential, as well as the phosphorylation of p38 mitogen-activated protein kinase (MAPK) in HUVECs. These data suggested that madecassoside could protect HUVECs from oxidative injury, which was probably achieved by inhibiting cell apoptosis via protection of mitochondria membranes and downregulation of the activation of caspase-3 and p38 MAPK.

Novel mitochondria-targeted antioxidant peptide ameliorates burn-induced apoptosis and endoplasmic reticulum stress in the skeletal muscle of mice

This study tested the hypothesis that a novel mitochondria-targeted SS-31 peptide attenuates the burn injury-induced apoptosis and endoplasmic reticulum stress and improves insulin sensitivity in the skeletal muscle. Following 30% total body surface area burn or sham burn, mice were injected daily with SS-31 peptide (5 mg/kg body weight), and the rectus abdominis muscles collected on postburn days 1, 3, and 7. The tissues were subjected to various biochemical and immunohistochemical analyses. Treatment with SS-31 peptide prevented burn-induced increases in the caspase 3 activity (P < 0.05) and apoptosis (P < 0.01) on postburn day 7. The SS-31 peptide treatment also prevented the increase in the expression levels of phosphatase and tensin homolog on postburn days 3 and 7. Burn injury-induced increases in the levels of two endoplasmic reticulum stress markers, binding immunoglobulin protein and protein disulfide isomerase, were significantly decreased by the SS-31 peptide treatments on postburn day 7 and on day 3 for binding immunoglobulin protein as well (P < 0.05). The effects of SS-31 appear to be, in part, due to its ability to reduce oxidative stress in burned mice, evidenced by reduced expression of oxidized proteins that were clearly evident on postburn day 7. Our results demonstrate a possible therapeutic potential of SS-31 peptide to ameliorate the adverse effects of burn injury in skeletal muscle.

Reduced oxidative tissue damage during endotoxemia in IRAK-1 deficient mice

The generation of reactive oxygen species (ROS) triggered by bacterial endotoxin lipopolysaccharide (LPS) plays a key role during the pathogenesis of sepsis. Given the key role that the interleukin-1 receptor associated kinase-1 (IRAK-1) plays in LPS-mediated Toll-like-receptor 4 (TLR4) pathway, we herein tested whether deletion of IRAK-1 gene in mice may render protection from LPS-induced oxidative tissue damage. In this report, we studied the levels of oxidative stress in vital organs including liver, kidney, and brain from wild type (WT) and IRAK-1 deficient mice injected with a lethal dose of LPS (25mg/kg), a TLR4-specific agonist. We demonstrated that LPS challenge induced marked elevation of lipid peroxidation and nitrite levels in the plasma and tissues of WT mice, as well as elevated pro-inflammatory mediators. In contrast, IRAK-1 deficient mice had significantly lower lipid peroxidation and nitrite levels, as well as lower levels of pro-inflammatory mediators. Mechanistically, LPS triggered higher levels of iNOS activity and elevated membrane translocation of p47(phox), a key component of NADPH oxidase in immune cell derived from WT mice compared to IRAK-1 deficient mice. Additionally, tissues harvested from WT mice injected with LPS exhibited reduced activities of anti-oxidant enzymes including glutathione peroxidase (GPx), catalase, and superoxide dismutase (SOD). In contrast, LPS challenge failed to reduce the activities of GPx and SOD in IRAK-1 deficient tissues. As a consequence, LPS caused significantly pronounced damage to liver and kidney tissues in WT mice as compared to IRAK-1 deficient mice.

Steroid receptor coactivator-3 differentially regulates the inflammatory response in peritoneal macrophages

Steroid receptor coactivator-3 (SRC-3) is a transcriptional coactivator that plays an important role in the regulation of cytokine mRNA translation. In the present study, SCR-3 gene knockout mice were used to study the effects of SCR-3 on the regulation of the inflammatory response in peritoneal macrophages induced by lipopolysaccharides (LPS). Peritoneal macrophages (PMs) of SRC-3^−/− mice showed a decrease in the release of TNF-α, IL-1β and IL-6, and an increase in the release of IL-10. Furthermore, results of RT-PCR also showed that levels of TNF-α, IL-1β and IL-6 mRNA expression were significantly lower, while the level of IL-10 mRNA expression was higher in the SRC-3^−/− mice, compared to those of wild-type mice, following treatment with LPS (p<0.01). In addition, western blotting revealed that: i) the extent of reduction of the glucocorticoid receptor in PMs from SRC-3^−/− mice was significantly lower than that in wild-type mice (p<0.01); ii) the extent of increase of AP-1 in PMS from SRC-3^−/− mice was significantly lower than that in wild-type mice (p<0.01); iii) the extent of increase of NF-κB p65 in PMs from SRC-3^−/− mice was significantly higher than that in wild-type mice (p<0.01). Collectively, our studies revealed that SRC-3 may play a key role in the maintenance of innate immunity. Furthermore, absence of the SRC-3 protein may result in the partial loss of inflammation and phagocytosis barrier function, including suppression of LPS-induced transcriptional activity, release of TNF-α, IL-1β and IL-6, and obstruction of the function of phagocytes and elimination of bacteria, as well as their production.

Burn and smoke injury activates poly(ADP-ribose)polymerase in circulating leukocytes

The nuclear enzyme poly(ADP-ribose)polymerase (PARP) plays a significant role in the pathogenesis of various forms of critical illness. DNA strand breaks induced by oxidative and nitrative stress trigger the activation of PARP, and PARP, in turn, mediates cell death and promotes proinflammatory responses. Until recently, most studies focused on the role of PARP in solid organs such as heart, liver, and kidney. We investigated the effect of burn and smoke inhalation on the levels of poly(ADP-ribosylated) proteins in circulating sheep leukocytes ex vivo. Adult female merino sheep were subjected to burn injury (2× 20% each flank, 3 degrees) and smoke inhalation injury (insufflated with a total of 48 breaths of cotton smoke) under deep anesthesia. Arterial and venous blood was collected at baseline, immediately after the injury and 1 to 24 h after the injury. Leukocytes were isolated with the Histopaque method. The levels of poly(ADP-ribosyl)ated proteins were determined by Western blotting. The amount of reactive oxygen species was quantified by the OxyBlot method. To examine whether PARP activation continues to increase ex vivo in the leukocytes, blood samples were incubated at room temperature or at 37°C for 3 h with or without the PARP inhibitor PJ34. To investigate whether the plasma of burn/smoke animals may trigger PARP activation, burn/smoke plasma was incubated with control leukocytes in vitro. The results show that burn and smoke injury induced a marked PARP activation in circulating leukocytes. The activity was the highest immediately after injury and at 1 h and decreased gradually over time. Incubation of whole blood at 37°C for 3 h significantly increased poly(ADP-ribose) levels, indicative of the presence of an ongoing cell activation process. In conclusion, PARP activity is elevated in leukocytes after burn and smoke inhalation injury, and the response parallels the time course of reactive oxygen species generation in these cells.

Role of the PPAR-α agonist fenofibrate in severe pediatric burn

Fenofibrate is a peroxisome proliferator activated receptor alpha agonist that contains both pro and anti-inflammatory properties, and has been used in the treatment of dyslipidemia and diabetes for decades. Its receptors are expressed in the liver, skeletal muscle, cardiac, enteric, and renal cells, which allow it to provide systemic regulation of lipoprotein metabolism, fatty acid oxidation, and fatty acid transport. Hyperglycemia is a common complication found in the burn population because hepatic glucose production and catecholamine-mediated hepatic glycogenolysis are augmented. Insulin resistance occurs often in these patients and is associated with poor outcomes. In the pediatric burn population, fenofibrate has been found to ameliorate or decrease the number of hypoglycemic episodes when compared to management with insulin alone. Its mechanism of action is thought to involve an improvement in insulin signaling in skeletal muscle, as well as improvements in mitochondrial function, glucose oxidation, and insulin sensitivity. The long term use of fenofibrate in severely burned patients may improve hyperglycemia and insulin resistance, as well as improve wound healing, and reduce apoptosis, and oxidative stress.

Propagation of cutaneous thermal injury: a mathematical model

Cutaneous burn wounds represent a significant public health problem with 500,000 patients per year in the USA seeking medical attention. Immediately after skin burn injury, the volume of the wound burn expands due to a cascade of chemical reactions, including lipid peroxidation chain reactions. Such expansion threatens life and is therefore highly clinically significant. Based on these chemical reactions, the present paper develops for the first time a three-dimensional mathematical model to quantify the propagation of tissue damage within 12 hours post initial burn. We use the model to investigate the effect of supplemental antioxidant vitamin E for intercepting propagation. We show, for example, that if tissue levels of vitamin E tocotrienol are increased, postburn, by five times then this would slow down the lipid peroxide propagation by at least 50%. We chose the alpha-tocotrienol form of vitamin E as it is a potent inhibitor of 12-lipoxygenase, which is known to propagate oxidative lipid damage. Our model is formulated in terms of differential equations, and sensitivity analysis is performed on the parameters to ensure the robustness of the results.

Increased poly(ADP-ribosyl)ation in skeletal muscle tissue of pediatric patients with severe burn injury: prevention by propranolol treatment

Activation of the nuclear enzyme poly(ADP-ribose) polymerase (PARP) has been shown to promote cellular energetic collapse and cellular necrosis in various forms of critical illness. Most of the evidence implicating the PARP pathway in disease processes is derived from preclinical studies. With respect to PARP and burns, studies in rodent and large animal models of burn injury have demonstrated the activation of PARP in various tissues and the beneficial effect of its pharmacological inhibition. The aims of the current study were to measure the activation of PARP in human skeletal muscle biopsies at various stages of severe pediatric burn injury and to identify the cell types where this activation may occur. Another aim of the study was to test the effect of propranolol (an effective treatment of patients with burns) on the activation of PARP in skeletal muscle biopsies. Poly(ADP-ribose) polymerase activation was measured by Western blotting for its product, poly(ADP-ribose) (PAR). The localization of PARP activation was determined by PAR immunohistochemistry. The results showed that PARP becomes activated in the skeletal muscle tissue after burns, with the peak of the activation occurring in the middle stage of the disease (13-18 days after burns). Even at the late stage of the disease (69-369 days after burn), an elevated degree of PARP activation persisted in some of the patients. Immunohistochemical studies localized the staining of PAR primarily to vascular endothelial cells and occasionally to resident mononuclear cells. There was a marked suppression of PARP activation in the skeletal muscle biopsies of patients who received propranolol treatment. We conclude that human burn injury is associated with the activation of PARP. We hypothesize that this response may contribute to the inflammatory responses and cell dysfunction in burns. Some of the clinical benefit of propranolol in burns may be related to its inhibitory effect on PARP activation.

Markers of oxidative stress after ablation of atrial fibrillation are associated with inflammation, delivered radiofrequency energy and early recurrence of atrial fibrillation

BACKGROUND

The role of oxidative stress after radiofrequency ablation of atrial fibrillation (AF) has not yet been well characterized. We sought to evaluate the time course of biomarkers of oxidative stress and inflammation after AF ablation and their association with clinical variables.

METHODS

Thirty consecutive patients (57.9 ± 1.7 years, 63% males) with paroxysmal AF underwent pulmonary vein isolation and ablation of complex fractionated atrial electrograms. Biomarkers were determined in blood samples before ablation and 6 h, 1, 2, 7, 30, 90 and 180 days post-ablation.

RESULTS

The pro-oxidant enzyme myeloperoxidase and oxidized low-density lipoprotein reflecting oxidant damage of lipoproteins increased 2.9 ± 0.2-fold and 1.2 ± 0.1-fold, respectively, and were significantly up-regulated until day 2 post-ablation. The anti-oxidant enzyme copper/zinc superoxide dismutase did not change significantly. Inflammatory markers significantly increased (high-sensitivity C-reactive protein (hs-CRP): 41 ± 8-fold; interleukin-6: 4.4 ± 0.7-fold) for 7 and 2 days, respectively. The increase of myeloperoxidase and hs-CRP was interrelated and both predicted early recurrence of AF within the first post-ablation week (both p < 0.05). The increase of both markers was associated with the amount of delivered radiofrequency energy (p < 0.05). The up-regulation of hs-CRP correlated with troponin T (p = 0.008), while myeloperoxidase and troponin T were borderline associated (p = 0.054). However, the oxidative and inflammatory responses did not predict long-term ablation outcome (p > 0.05).

CONCLUSIONS

Markers of oxidative stress showed a significant up-regulation during the first 2 days after AF ablation. Their up-regulation was linked to inflammation, delivered radiofrequency energy, and early recurrence of AF, but did not predict long-term ablation outcome.

Down-regulation of glutatione S-transferase α 4 (hGSTA4) in the muscle of thermally injured patients is indicative of susceptibility to bacterial infection

Patients with severe burns are highly susceptible to bacterial infection. While immunosuppression facilitates infection, the contribution of soft tissues to infection beyond providing a portal for bacterial entry remains unclear. We showed previously that glutathione S-transferase S1 (gstS1), an enzyme with conjugating activity against the lipid peroxidation byproduct 4-hydroxynonenal (4HNE), is important for resistance against wound infection in Drosophila muscle. The importance of the mammalian functional counterpart of GstS1 in the context of wounds and infection has not been investigated. Here we demonstrate that the presence of a burn wound dramatically affects expression of both human (hGSTA4) and mouse (mGsta4) 4HNE scavengers. hGSTA4 is down-regulated significantly within 1 wk of thermal burn injury in the muscle and fat tissues of patients from the large-scale collaborative Inflammation and the Host Response to Injury multicentered study. Similarly, mGsta4, the murine GST with the highest catalytic efficiency for 4HNE, is down-regulated to approximately half of normal levels in mouse muscle immediately postburn. Consequently, 4HNE protein adducts are increased 4- to 5-fold in mouse muscle postburn. Using an open wound infection model, we show that deletion of mGsta4 renders mice more susceptible to infection with the prevalent wound pathogen Pseudomonas aeruginosa, while muscle hGSTA4 expression negatively correlates with burn wound infection episodes per patient. Our data suggest that hGSTA4 down-regulation and the concomitant increase in 4HNE adducts in human muscle are indicative of susceptibility to infection in individuals with severely thermal injuries.

The dynamics of the early inflammatory response in double-hit burn and sepsis animal models

Severe burn trauma is generally associated with bacterial infections, which causes a more persistent inflammatory response with an ongoing hypermetabolic and catabolic state. This complex biological response, mediated by chemokines and cytokines, can be more severe when excessive interactions between the mediators take place. In this study, the early inflammatory response following the cecum ligation and puncture (CLP) or its corresponding control treatment (sham-CLP or SCLP) in burn (B) male rats was analyzed by measuring 23 different cytokines and chemokines. Cytokines and chemokines, including MCP-1, IP-10, leptin, TNF-α, MIP-1α, IL-18, GMCSF, RANTES and GCSF were significantly altered in both B+CLP and B+SCLP groups. IL-10 and IL-6 were significantly up-regulated in the B+CLP group when compared to the B+SCLP group. Down regulation of leptin and IP-10 concentrations were found to be related to surgery and/or infection. IL-18 and MCP-1 were elevated in all groups including previously published single injury models receiving similar treatments. In this study, insult-specific mediators with their characteristic temporal patterns were elucidated in double hit models.

Evaluation of the antioxidant peptide SS31 for treatment of burn-induced insulin resistance

After severe burn injury and other major traumas, glucose tolerance tests demonstrate delayed glucose disposal. This 'diabetes of injury' could be explained by insulin deficiency, and several studies have shown that soon after trauma (ebb phase) insulin concentrations are reduced in the face of hyperglycemia. After resuscitation of trauma patients (flow phase), β-cell responsiveness normalizes and plasma insulin levels are appropriate or even higher than expected, however, glucose intolerance and hyperglycemia persist. In the acute care setting, several approaches have been used for treating insulin resistance, including insulin infusion, propranolol and glucagon-like-peptide-1 (GLP-1). Recently, it was demonstrated that a tetrapeptide with antioxidant properties D-Arg-Dmt-Lys-Phe-NH2 (SS31), but not its inactive analogue Phe-D-Arg-Phe-Lys-NH2 (SS20) attenuates insulin resistance in mice maintained on a high fat diet. In this report the effects of SS31 and SS20 on burn-induced insulin resistance was studied in mice. Oral glucose tolerance tests (OGTT) were performed in 4 groups of 6 mice with thermal injury with or without pre-treatment with SS31 or SS20 and sham controls. In addition, biodistribution of 18FDG was measured in burned mice with and without SS31 treatment and shams (subsets of these animals were also studied by µPET). For comparison purposes, groups of 6 cold-stressed mice with and without SS31 treatment were also studied. The results of these studies demonstrate that SS31 but not SS20 ameliorated burn-induced insulin resistance. In addition, SS31 treatment resulted in marked reduction in the increased 18FDG uptake by brown adipose tissue (BAT) in burned but not cold-stressed animals; suggesting that the stressors act by different mechanisms. Overall, these studies confirmed that SS31 can be used to reverse burn-induced insulin resistance and provide a firm pre-clinical basis for future clinical trials of SS31 for the treatment of insulin resistance in patients with burn injury.

Efficacy and tolerability of fitostimoline in two different forms (soaked gauzes and cream) and citrizan gel in the topical treatment of second-degree superficial cutaneous burns

A total of 227 patients (mean age 41.3 years, 52% females) with at least one second-degree superficial cutaneous burn of thermal origin of a smallest transverse diameter ≥20 mm and a largest transverse diameter ≤90 mm were randomised to receive the topical application of aqueous extract of Triticum vulgare (Fitostimoline) in two different forms (soaked gauzes and cream) or catalase of horse origin in form of gel (Citrizan Gel), given up to healing or to a maximum of 20 days. The rate of lesion healing at end of study was significantly higher in patients treated with Fitostimoline (gauzes 97.3%, cream 91.5%) than in those receiving catalase (84.5%). The pooled Fitostimoline groups were also significantly more effective than catalase gel in reducing total symptoms score, pain at medication, pain at rest, and burning at end of study. Both formulations of Fitostimoline and catalase gel were well tolerated in terms of adverse effects in the site of application.

Plasma proteome response to severe burn injury revealed by 18O-labeled "universal" reference-based quantitative proteomics

A burn injury represents one of the most severe forms of human trauma and is responsible for significant mortality worldwide. Here, we present the first quantitative proteomics investigation of the blood plasma proteome response to severe burn injury by comparing the plasma protein concentrations of 10 healthy control subjects with those of 15 severe burn patients at two time-points following the injury. The overall analytical strategy for this work integrated immunoaffinity depletion of the 12 most abundant plasma proteins with cysteinyl-peptide enrichment-based fractionation prior to LC-MS analyses of individual patient samples. Incorporation of an 18O-labeled "universal" reference among the sample sets enabled precise relative quantification across samples. In total, 313 plasma proteins confidently identified with two or more unique peptides were quantified. Following statistical analysis, 110 proteins exhibited significant abundance changes in response to the burn injury. The observed changes in protein concentrations suggest significant inflammatory and hypermetabolic response to the injury, which is supported by the fact that many of the identified proteins are associated with acute phase response signaling, the complement system, and coagulation system pathways. The regulation of approximately 35 proteins observed in this study is in agreement with previous results reported for inflammatory or burn response, but approximately 50 potentially novel proteins previously not known to be associated with burn response or inflammation are also found. Elucidating proteins involved in the response to severe burn injury may reveal novel targets for therapeutic interventions as well as potential predictive biomarkers for patient outcomes such as multiple organ failure.

High-dose antioxidant administration is associated with a reduction in post-injury complications in critically ill trauma patients

BACKGROUND

We recently demonstrated a high-dose antioxidant (AO) protocol was associated with reduction in mortality. The purpose of this study was to evaluate the impact of AO on organ dysfunction and infectious complications following injury.

PATIENTS AND METHODS

High-dose AO protocol: ascorbic acid 1000 mg q 8 h, alpha-tocopherol 1000 IU q 8 h, and selenium 200 mcg qd for 7-day course. Retrospective cohort study evaluating all patients admitted after protocol implementation (AO+), October 1, 2005 to September 30, 2006. Comparison cohort (AO-): all patients admitted in the year prior to implementation, October 1, 2004 to September 30, 2005.

RESULTS

2272 patients included in the AO+ group, 2022 patients in the AO- group. Demographics and injury severity were similar. Abdominal compartment syndrome (ACS) (2.9% vs. 0.7%, <0.001), surgical site infections (2.7% vs. 1.3%, p=0.002), pulmonary failure (27.6% vs. 17.4%, p<0.001), and ventilator-dependent respiratory failure (10.8% vs. 7.1%, p<0.001) were significantly less in the AO+ group. Multivariate regression showed 53% odds reduction in abdominal wall complications and 38% odds reduction in respiratory failure in the AO+ group.

CONCLUSIONS

Implementation of a high-dose AO protocol was associated with a reduction in respiratory failure and ventilator-dependence. In addition, AO were associated with a marked decrease in abdominal wall complications, including ACS and surgical site infections.

α-Tocopherol adipose tissue stores are depleted after burn injury in pediatric patients

BACKGROUND

We previously showed that thermal injury depletes plasma vitamin E in pediatric burn patients; however, plasma changes may reflect immediate alterations in vitamin E nutriture. Adipose tissue α-tocopherol concentrations are generally accepted to reflect long-term vitamin E status.

OBJECTIVE

To test the hypothesis that thermal injury depletes body stores of vitamin E, α-tocopherol concentrations were measured in adipose tissue samples.

DESIGN

Pediatric patients (n = 8) were followed up to 1 y after burn injury. Surgically obtained samples were collected at various intervals and stored at -80°C in a biorepository. α- and γ-Tocopherols, cholesterol, and triglycerides were measured in the same tissue aliquot.

RESULTS

During the first week after injury, adipose tissue α-tocopherol concentrations were within the expected normal range of 199 ± 40 nmol/g adipose tissue but were substantially lower at weeks 2 and 3 (133 ± 13 and 109 ± 8 nmol/g adipose tissue, respectively). Individual rates of decrease, estimated by linear regression, showed that adipose tissue α-tocopherol decreased by an average of 6.1 ± 0.6 nmol/g daily. During the first month after injury, adipose tissue triglyceride concentrations also decreased, whereas no changes in cholesterol concentrations occurred.

CONCLUSIONS

These data emphasize that the burn injury experienced by these pediatric patients altered their metabolism such that vitamin E status diminished during the month after injury. Further studies are needed to evaluate the mechanism and consequences of the observed vitamin E depletion. This trial was registered at clinicaltrials.gov as NCT00675714.

Oxidative stress, systemic inflammation, and severe periodontitis

Periodontal infections have been associated with a state of chronic inflammation. To ascertain whether severe periodontitis and its treatment are associated with oxidative stress, we recruited 145 cases (periodontitis) and 56 controls in a case-control study. A further pilot intervention study of 14 cases (periodontal therapy) was performed. Blood samples were taken at baseline (case-control) and 1, 3, 5, 7, and 30 days after treatment (intervention). Diacron-reactive oxygen metabolites (D-ROM), anti-oxidant potential, C-reactive protein (CRP), interleukin-6, and lipid profiles were determined with high-sensitivity assays in serum. Patients with severe periodontitis exhibited higher D-ROM levels (P < 0.001) and lower total anti-oxidant capacity (P < 0.001) compared with healthy control individuals. These findings were independent of age, gender, smoking habits, ethnicity, and standard lipids differences. D-ROM levels were positively correlated with CRP (R = 0.4, P < 0.001) and clinical periodontal parameters (R = 0.20, P < 0.05). Acute increases of D-ROM (P < 0.01) were observed following periodontal therapy. Analysis of these data suggests a positive association between severe periodontitis and oxidative stress.